1. Field of the Invention
The present invention relates to a device such as a digital multifunction peripheral (MFP), a control method thereof, and a program for realizing the control method.
2. Description of the Related Art
A wireless communication system for sharing a device, such as a single digital MFP, with a plurality of host computers has conventionally been generally known. The term “digital MFP” refers to a device in which a plurality of functions, such as copy, facsimile, printer, scanner, and memory card reader/writer, are consolidated in a single device.
In such a wireless communication system, a host computer has used a detachable memory card provided in the device as a file system. More specifically, in such a technique, a host computer which has established a wireless connection uses the contents of a memory card attached to the device as a file system. A user of the host computer can attach the memory card to a device provided with a memory card reader/writer, and perform reading and writing processing of the data on the memory card.
In such a wireless communication system, examples of security technology for data on a memory card include a technique described in Japanese Patent Application Laid-Open No. 2008-210154. In the technique described in Japanese Patent Application Laid-Open No. 2008-210154, information (specifying information) for specifying a host computer which can access the memory card is stored in the memory card in advance. When a device detects that the memory card has been attached, the device acquires the specifying information from the memory card. Then, using this specifying information as access control information, the device controls so that only access to the memory card from the host computer corresponding to the specifying information is permitted.
However, the wireless communication system which has an access control configuration for the memory card such as that in Japanese Patent Application Laid-Open No. 2008-210154 has the following drawbacks.
Since information (specifying information) for specifying the host computer needs to be stored in the memory card in advance, a user is forced to perform a troublesome operation to do that. Further, in some cases the specifying information may not be stored in the memory card to be used. In such a case, the same problem will occur as with a device that is not provided with a special access control configuration for a memory card. More specifically, during a period from immediately after the user of the host computer has attached the memory card to the device and finished reading and writing the data on the memory card until the memory card is detached, a user of another host computer can access the memory card. Consequently, there is a security problem with the information in the memory card.
This point will now be described in more detail by referring to a sequence diagram illustrated in FIG. 15.
A case will be considered in which, while a host computer 1 is accessing a memory card attached to a digital MFP, another host computer 2 issues a memory card job processing request (T310 in FIG. 15) to the digital MFP to try to access another person's memory card.
The host computer 1 issues a memory file unmount (T304) to the digital MFP to end use of the memory card as a file system, thereby completing access to the memory card. However, if the memory card remains mounted on the digital MFP, the digital MFP receives a memory card job from the other host computer 2. In other words, in response to the memory card job processing request (T310) issued from the other host computer 2, the digital MFP responds normally to the memory job from the host computer 2, such as a memory file mount (T312) or a memory file operation (T313).